Influence of $A$ -Site Deficiency on Magnetocaloric Effect in Nonstoichiometric $({\rm La}_{0.8}{\rm Ca}_{0.2})_{0.975}{\rm MnO}_{3.01}$

Abstract

Manganite perovskite with A-site deficiency has been synthesized by a solid-state reaction technique. Our work does not support a general view that A-site deficiency gives a decrease on Curie temperature. The Curie temperature of (La 0.8 Ca 0.2) 0.975 MnO 3.01 is 188 K with maximum entropy change -δS M max = 1.6 J·kg -1 ·K -1 and refrigerant capacity (RC) of 27 J/kg under an applied field of 10 kOe. The nonstoichiometric (La 0.8 Ca 0.2) 0.975 MnO 3.01 may offer a wider temperature span of 240% compared with those nanocrystalline (La 0.8 Ca 0.2) 0.975 MnO 3.01 that have similar RC, which has been reported by others.